Pitot plug for fluid-meters.



' J. WILKINSON.

PITOT PLUG FOR FLUID METERS.

APPLICATION FILED AUG. 5, 1912.

Patented Apr. 14, 1914.

r o t m v I JamesVW|Kins0n,

Witness es: 7%

I Muss wrmnnson,

OF BOSTON, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

rrro'r PLUG non FLUID-METERS.

roac es.

Specification of Letters Patent. Application filed August 5, 1912. Serial No. 713,2 85. 1

Patented Apr. id, 1914.

Eb all whom it may concern:

"Be it known that 1, JAMES VVILKINSQN, a citizen of the United States, residing at Boston, inthe county of Suffolk and State oflid assachusetts have invented certain new and, useful Improvements in Pitot Plugs for Fluid-Meters, of which the following is a specification.

This invention relates to meters for,

,iheasuring the flow of fluids in mains, and has-especial reference to what is known as the Pitot tube plug by means of which a pressure difference is set up in the two legs of a mercury receptacle, in order that the varying levels of the mercury in said legs may be utilized to give information as to variations oi the flow of the fluid passing through the main. The nozzles of such Pitot tubes are connected with the mercury rece'ptacle by means of pipes in which the water of condensation collects, if the fluid to be metered is steam. "When variations occur in the pressures in said pipes there is a loss of this water due to its being forced out of one of the pipes by the movement of the mercury. At the same time the water level is correspondingly lowered in the other pipe and until this level is restored to normal by further condensation, the indications of the meter are not accurate due to thc'change in the hydraulic head. This introduces into the problem an uncertain time element for which it is difficult to compensate. I

The object 0t 'my invention is to provide a Pit otplugin which the water in the two pipes c'an be transferred from one to the other when variations in flow take place, without loss and change of head andhence withoutinterfering. with the proper func' tioning of the Pitot. tube as an accurate generator of pressure differences due to flow. In order to accomplish this, I make the Pitot plug of two parallel tubes connected along their adjacent sides by a capillary slit which is open on one side to the action of the column of fluid flowing through the main. The pressure of the fiuid prevents the Water from escaping from the tubes, and yet the interior of said tubes is practically open for the action of the varying pressures produced by said flow of fluid, While the water filling the tubes can pass freely from one to the other in a thin capillary sheet through said slit.

The invention is illustrated in the accompanying drawing, in which-- Figure 1 is a longitudinal section of a steam main equipped with my improved Pitot plug; Fig. 2 is an end view of the base of said plug; Fig. 3 is a cross scctionon the line 33, Fig. 1; and Fig. 4c' is diagramfmatic view of the Pitot plug connected to a The plug has a base 1 which is screwthreaded so that it can be inserted into a tapped openingin the wall of the steam main 2, a polygonal collar l being provided on the base for reception in a wrench. Inserted in said base is a double tube device 4 whose cross section is rmighly the outline of a dumb-bell, the two tubular portions or members 6 being parallel and connected by anarrow web 7. A. capillary slit 8 runs lengthwise of the web and connects the channels in the two members dalon'g their adj acent sides. A narrow opening 9 runs length wise of said slit on one side and puts it in connnunication with the main .2. The walls of the tubes 5, 6 on the same side as the opening 9 are inclined or beveled toward each other, forming the lips 5", 6 adjacent to the opening as clearly shown in Fig. 3. The outer ends of the a cap 10.

In the base are four sockets for receiving the two pipes 11 connected to the mercury receptacle of the meter, means for intuhes are closed by dicating the pressure difference in the channels of the Pitot tube device, this meter means being shown by way of illustration in Fig. t. as a Ll-shaped tube. Two of these sockets 12 communicate by passages 13 with the tube 5, while the other two,

14, are connected by passages 15 with the tube 6. Four sockets are provided so. that the same plug can ,be'uscd for horizontal and vertical pipes if desired, but only two of the sockets, via, one of the sockets 1'2 and one of the sockets 14, are used at one time, the other two being closed by screw plugs.

The nozzle is inserted into' the main in such a position that it will be horizontal and the fiowof the fluid will be parallel with the plane of the narrow slit 8. The column of fluid strikes the outer surface of the tube 5 and follows it around to the opening 9 through which it has access to the interior'of the tubes. The incline oi thclip 5 directs the fluid toward the tube 6 and away from the tube 5, so that the former becomes the leading tube and the latter the trailing tube of the device, the greater pressure being set up in the tube 6. Now when the tubes become filled with water of condensation, the fluid sweeping over them cannot actually enter through the opening 9 but it nevertheless has an active effect upon the water filling the tubes, so that different pressures are exerted upon the ends of the mercury column. If now a variation in the pressure difference causes a movement of the water and mercury in the tubes, said water will not be forced out of the tubes into the main, but will pass in a thin capillary film across the rear of the slit 8 along the wall formed. by the web, being transferred in this manner from one tube to the other without any loss or changein level of the tops of the water columns in the pipes, both levels being at the center of the plug. This is accomplished without interfering with the effect produced by the variation in pressure due to the change in the velocity of the fluid. The result is that the meter operates always in an accurate manner and without the introduction of vexatious and ,uncertain time elements. i

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to' have it understood that the apparatus shown is only illustrative and that the, invention can be carried out by other means.

' What I claim as new and desire to secure by Letters Patent of the United States, is: 40'

1. A Pitot device comprising two channels open to the action 0 the flowing fluid to be metered and communicating with one another independently of the means for indicating their pressure difference so that durin operation water of condensation may pass rom one channel to the other. 2. A Pitot plu provided with two 'members that are acted upon by the flowing fluid, and having means independent of that for indicating the pressure difl'erence produced by said members Tor transferring water of condensation from one member to the other during operation.

3. A Pitot plug 'comprisin t'wo parallel tubes open to the action of t e fluid to be metered and means independent of that for indicating the pressure difference reduced;

by said members for transferring rom'one tube to the other water of condensation filling said tubes. i f

4. A Pitot plug comprisin ,tiirdp'arallel tubes open to the action of t e fluid to be metered, and means independent of that for indicating the pressure difi'erence produced I the water of condensation-filling said tu s. 1

6. A Pitot plug comprising two parallel tubes and a web connecting them and having a capillary slit lengthwise thereof which connects the interiors of said tubes and a longitudinal opening enteringthe slit for the admission of pressurefrom the fluid to be metered. v

7. A Pitot plug comprising two parallel tubes and a web between them having a longitudinal slit connecting the tubes, there be- 1 ing a longitudinal opening entering the slit, and said tubes having inclined lips adjacent the opening.

8. vIn combination, a U-tube containing a column of liquid, amain through which the fluid to be measured flows, a Pitot plug arranged in the main and having members on which the flowing fluid acts to create diifer ent pressures therein that have a definite relation to the rate of flow, conduits con I heating the pluv to the U-tube, water of condensation collecting in said plug'and conduits, and means for transferring water of condensation from one member of the plug to the other when the column of liq:

uid in the U-tube moves as the How varies,

In. witness whereof, I have hereunto set my hand this 3rd day of August, 1912.

JAMES .WILKINSON.

Witnesses:

BENJAMIN B. IIUTIL HELEN Onronn.

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